Integrated fastener and sealing system for plumbing fixtures

ABSTRACT

A metallic bolt fastener assembly that includes a threaded shank, a head and an end, the head and a portion of the shank encapsulated with a polymer composition. The polymer composition includes a polymer material such as natural rubber, synthetic rubber or thermal plastic materials. The polymer composition provides improved corrosion resistance and superior fluid sealing properties when used as a water tank-to-toilet bowl or other similar plumbing fixture connection system.

INCORPORATION BY REFERENCE

This invention relates to fasteners and, more particularly, to anencapsulated fastener utilized to assemble two or more components of aplumbing fixture. U.S. Pat. No. 6,436,474 to Godsted discloses a methodof coating fasteners and is incorporated by reference as backgroundmaterial for showing the same. U.S. Pat. No. 7,165,293 to Musildiscloses a conveyor fastener and is incorporated by reference asbackground material for showing the same.

This invention relates to a fastener and, more particularly, to afastener with an integral encapsulated portion that is utilized toassemble two or more components of a plumbing fixture.

BACKGROUND OF THE INVENTION

Traditional toilet assembly design utilized bolt fasteners to connectthe tank to the bowl with a polymer washer on the inside of the tankthrough two pieces of vitreous china followed by a steel washer and afastener nut on the outside of the bowl. This assembly was intended notonly to mechanically secure the tank to the bowl, but also prevent thewater or water/chemical fluids from leaking out of the tank. Once thebolts, steel and polymer washers and nuts were assembled in the properorder, each fastener assembly was tightened using wrenches and/orscrewdrivers. In addition to the labor intensive nature of this process,components of the fastener assembly were lost and assemblies wereimproperly secured. In addition, washer components often only provided amarginal compression seal often resulting in leaks from the tank. Due tothe design of this fastening system, the metallic bolt is continuouslysubmerged in water on the inside of the tank and exposed to condensatewater on the outside of the tank. These conditions cause corrosion ofthe bolt, which, in turn, can result in leaks and/or difficulty inremoving the bolts when servicing the toilet.

Fasteners, such as bolts of mild or stainless steel, brass or othermetals, that are to be exposed to moisture and chemicals used in theplumbing industry are typically made from bars or rods that may havebeen bare or plated or galvanized, usually with zinc. The platingprocess is typically either by electrolytic deposition of zinc or viadipping the bolt fastener into a molten zinc bath or pot. The latter ischaracterized as a “hot dipping” process.

The metal used for these bolt fasteners may be composed of variousalloys that demonstrate significant property differences depending uponthe degree of cold working, differences in the basic metal constituents,and whether or not a stress relieving (patenting or annealing) processstage has been introduced.

Such bare and plated bolt fasteners are commonly used in the plumbingindustry. In the case of a toilet, several (typically two or three) boltfasteners were used to mechanically connect the water holding vessel,commonly referred to as the “tank”, to the toilet bowl. This wasaccomplished by inserting the bolt through matching holes in the tankand bowl with a nut on the bowl side providing the balance of themechanical assembly between the tank and bowl. Since the bolt head andportion of the bolt shank immediately adjacent to the head are installedon the inside of the tank, they are continuously exposed to water andchemical additives. Corrosion is an electrochemical process that allowsa refined metal to revert to its native oxide state (rust). In order forcorrosion to occur, an electrolyte must be present. The water orwater/chemical mixture in the tank acts as this electrolyte and reactswith the exposed bolt surfaces causing them to corrode. When the boltcorroded, the fastener system was difficult or impossible to remove andreplace using common hand tools.

The portion of the bolt fastener shank that extends from the outside ofthe bowl and onto which the bolt has been assembled does not come intocontact with the water or water/chemical electrolyte on the inside ofthe tank. However, condensate water often forms on the exterior of thetank, especially in humid environments. This condensate water oftentravels down the bowl and onto the bolt fastener shank on the undersideof the bowl. Since condensate water also acts as an electrolyte,corrosion often occurred on the bolt shank making it difficult orimpossible to remove and replace the tank to bowl fastener using commonhand tools.

In order to improve the corrosion resistance of the bolt fasteners,improve the seal against tank leaks, improve ease of installation andreduce fastener assembly part count, there is a need or desire for afastener system that reduces corrosion and more effectively prevents thetank from leaking. There is also a need for a bolt fastener system thatis easier to install using the minimum number of commonly available handtools.

SUMMARY OF THE INVENTION

In accordance with the present invention, provided is a bolt fastenerthat combines mechanical connection function between the tank and bowlwith a sealing and an encapsulation feature into a single componentpart.

More particularly, provided is a polymer encapsulated fastener whereinthe head and a portion of its shank are encapsulated. This encapsulationcan be used to isolate the metallic components of the bolt fastener thatare installed on the inside of the tank from the corrosive water orwater/chemical electrolyte contained in the tank thus protecting thebolt from corrosion.

In one embodiment, the fastener assembly can be further protected fromcorrosion by applying a secondary coating. This coating can be anelectrochemically active, protective plating, such as a galvanic zinc,aluminum or magnesium, over substantially all of the metal surface priorto encapsulating the bolt head and shank to form a corrosion resistant,plated fastener. Because zinc is electrochemically more active than theunderlying metal bolt fastener, the relatively more electrochemicallypassive steel bolt fastener is protected from corrosion via the galvanicprocess. This adds to the corrosion resistance of the entire boltfastener. This plating is particularly important in preventing corrosionof the condensate water exposed bolt fastener shank under the bowl.

In another embodiment of the present invention, the fastener can includea sealing portion formed into the encapsulation. This can include ano-ring seal molded into a polymer encapsulation on the bottom flat faceof the encapsulated bolt head. In yet another embodiment, multiplesealing configurations can be included on the fastener. This can includesealing rings molded into the encapsulation that covers the bolt shankimmediately adjacent to the bolt fastener head. The circumferentialsealing rings would then be inserted through the pre-cast holes from theinside of the tank bottom using limited load force. The circumferentialsealing rings make contact with the outer edge of the pre-cast holes inthe tank, thus providing an improved water seal and preventing fluidfrom leaking from the tank.

With the foregoing in mind, it is a feature and advantage of theinvention to provide a bolt fastener assembly with a unique degree ofcorrosion resistance. This is accomplished by plating the surface of allmetallic components of the fastener assembly with a galvanic metal,which is anodic to the underlying bolt material.

It is also a feature and advantage of the invention to provide anencapsulation of the bolt fastener that provides a high integrityhydrostatic seal to prevent leaks from the tank. The invention cancreate a plurality of sealing points.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing, and more, will in part be obvious and in part be pointedout more fully hereinafter in conjunction with a written description ofpreferred embodiments of the present invention illustrated in theaccompanying drawings in which:

FIG. 1 is a side view of a fastener assembly according to an aspect ofthe present invention;

FIG. 2 is a sectional view taken along lines 2-2 in FIG. 1;

FIG. 3 is a bottom view of the fastener shown in FIG. 1;

FIG. 4 is a perspective view of a toilet that includes two of thefasteners shown in FIG. 1;

FIG. 5 is a sectional view taken along lines 5-5 in FIG. 4; and,

FIG. 6 is a flow diagram for a method of assembly for a fastener such asthe fastener shown in FIG. 1; and,

FIG. 7 is a flow diagram for another method of assembly a fastener suchas the fastener shown in FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now in greater detail to the drawings wherein the showings arefor the purpose of illustrating preferred embodiments of the inventiononly, and not for the purpose of limiting the invention, FIGS. 1-3 showa fastener bolt 10 having a fastener body 8 extending along axis S that,in this embodiment, is made from a metallic material and which includesan upper expanded head 16 and a bolt shaft 13 centered about axis S.Shaft 13 includes an elongated, non-threaded shaft portion 17 and alower threaded end portion 12.

Fastener 10 further includes an encapsulating portion 11 that is formedby a deformable material. In one embodiment, this portion is formed by amonolithic, polymeric material and is bonded to and encapsulates theexpanded head end 16 of the bolt and extends partway down the boltshaft.

The encapsulated portion includes an outer head surface 11 a, a lowerhead surface or lower flat face 11 b, a shaft surface 11 c and a threadfacing surface 11 d. As can be appreciated, the dimensions of thesesurfaces and the dimensions of the fastener body are dependent on theparticular application of fastener 10 and can change without detractingfrom the invention of this application which will be discussed ingreater detail below.

In another embodiment, encapsulation 11 includes one or more o-rings 14extending from surface 11 b which is immediately below the head portionof the bolt. As will also be discussed in greater detail below, o-ring14 can be used to help seal the opening in which fastener 10 extendsthrough.

Fastener 10 can further include one or more circumferential sealing ribs15 a and 15 b extending radially from surface 11 c. These ribs can beused by themselves or in combination with o-ring 14 to help seal theopening in which fastener 10 extends through.

Fastener 10 can also include a chamfer 25 at end 11 d to aid inpositioning the fastener into the opening in which fastener 10 extendsthrough. Further, ribs 15 a and 15 b can also include an angled leadingedge 24 a and 24 b, respectively, to help position the fastener in theopening while allowing a snug fit between the components.

While it has been found that this invention works particularly well withmetallic bolts, this invention has broader applications wherein theinvention is not limited to metallic bolts; but is also applicable tonon-metallic materials such as plastic or composite bolt materials. Inaddition, the bolt threads could extend the entire length of the shaftto the expanded head.

In yet another embodiment, body 10 is plated with an electrochemicallyactive, protective film, such as a galvanic zinc, aluminum or magnesium,over substantially the entire metal surface prior to encapsulating thebolt head and shank to form a corrosion resistant, plated fastener. Theprotective film can be applied by any method known in the art including,but not limited to, quenching the bolt in the molten, galvanic metal,through arc spraying or by electroplating.

The polymer encapsulation 11 is bonded to and molded around the expandedhead end 16 and a portion of the elongated shaft 17 of the bolt. Thiscan be done by placing the bolt in a mold of the shape of the finalmonolithic encapsulation 11, including the expanded head 19, o-ring 14and raised circumferential ribs 15. Uncured polymer compound is thenintroduced into the mold via compression, transfer or injection methodand is vulcanized using heat and pressure. While a wide range of pliablematerials can be used, it has been found that a monolithic encapsulationof natural or synthetic rubber works well for the encapsulation.However, other materials such as thermal plastics can also be used.

The polymer encapsulation should have sufficient thickness to provideadequate mechanical strength to withstand the use of hand tools, such asa wrench, pliers, vice grip or screw/nut drive, during the installationof fastener assembly. In one embodiment of the invention, a polymerencapsulation thickness of between 0.080″ and 0.188″ is used. However,greater or lesser thicknesses of encapsulation can be used depending onthe difference between the fastener bolt shaft 17 and the opening.Further, the thickness of the encapsulation can be used to allow onefastener body 8 to be used on multiple applications or holes.

With reference to FIGS. 4 and 5, shown is a toilet T having a tank 21and a bowl 22 with fastener openings 23 extending through both. In thisembodiment, the polymer encapsulation should have sufficient thicknessto provide adequate sealing properties in openings 23. In this respect,the encapsulation should be sized to snugly fit into openings 23 in bothtank 21 and bowl 22 to form a hydrostatic seal to prevent water Wcontained internally in the tank 21 from leaking to the outside of thetank 21 through fastener bolt holes 23 of the tank 21.

The polymer used for the encapsulation is to be soft enough to allow theo-ring 14 and/or circumferential ribs 15 to compress and form awater-tight seal on the inside of the tank 21. Desirably, a polymermaterial with a Durometer of between 60 and 70 is used. Materials with aDurometer ranging between 30 and 90 can also be used.

Installation

Also with reference to FIGS. 6 & 7, shown are the steps for installing afastener according to the present invention. More particularly, beforeinstalling the fastener assembly, the two or more fastener holes in thebottom of the toilet tank are aligned with the fastener installationholes on the top of the toilet bowl. Fastener 10 is then insertedthrough each of the holes in the tank and then through each aligned holein the bowl until a portion of bolt threads 12 extend from the bottom ofthe bowl. The circumferential ribs of the encapsulation are configuredto provide resistance as the fastener is inserted into the aligned holesin the tank and bowl, which is overcome with hand-applied pressure.

A metallic or non metallic nut 40 is then rotated onto each fastenerassembly's bolt threads. As can be appreciated, any nut known in the artcan be used without detracting from the invention of this application.Each nut is hand tightened into the position where the threaded boltextends from the bottom of the bowl. The top of each fastener 10 on theinside of the tank is held in place by hand or an appropriate hand toolwhile the nut below the bottom of the bowl is tightened using anappropriate hand or power tool. The nut is tightened until the integralo-ring portion of the polymeric encapsulation has completely compressedand the immediately adjacent flat bottom surface of the polymericencapsulation begins to compress against the inside bottom of the tank.

As can be appreciated, faster 10 can include any know tool receivingconfiguration without detracting form the invention of this application.This can include, but is not limited to flats 32 and 34 which are bestshown in FIG. 3, a flathead/slotted drive, a crosshead/phillips drive, apozdriv/supradriv drive, a torx drive, a hex/allen drive, a robertsondrive, a tri-wing drive, a torq-set drive, a spanner head drive, or evena triple square/XZN drive. Yet even further, the fastener can include notool receiving configuration without detracting from the invention ofthis application. In one embodiment, the faster can include acylindrical head with no tool receiving configuration. In even yetanother embodiment, the fastener can be configured such that ribs 15 aand 15 b and/or other portions of the encapsulation produce a resistancefit between the fastener and the fastener opening such that a tool isnot required to prevent rotation of the fastener relative to the holewhen the nut is tightened.

Compression of the o-ring and its immediately adjacent bottom flatsurface of the polymeric encapsulation against the inside bottom of thetank as each nut is tightened forms the desired hydrostatic seal at thebolt holes where the fastener assemblies are inserted. Thecircumferential sealing rings of the polymeric encapsulation around thebolt shaft add to the hydrostatic seal within the tank.

It will be apparent to those skilled in the art that the presentinvention is capable of further cooperative uses with other plumbingfixture related fastener components and systems. Accordingly, the usesfor our fastener assembly of the present invention are myriad and it isplain that the present invention provides utility beyond what isillustrated here.

With special reference to FIG. 6, one method of installation includesthe steps of:

Align fastener holes in tank and bowl;

Insert threaded end of fastener assembly according to the presentinvention through tank and bowl until threads extend below the bottom ofthe bowl hole;

Apply slight pressure to the encapsulated so that circumferential ribseals are inserted into the through hole of the tank;

Slide a metal washer over the threaded fastener assembly;

Rotate a nut onto the threaded shank of the fastener assembly; and,

Tighten the nut so that the torque is sufficient to compress the base ofthe polymeric fastener head, which is seated on the internal tank bottomsurface.

With special reference to FIG. 7, another method of installationincludes the steps of:

Insert threaded end of fastener according to the present inventionthrough tank hole and continue pushing in until the circumferential ribseals are in the hole of the tank;

Repeat for remaining fastener(s);

Set tank onto bowl while insuring threaded fastener ends go throughrespective holes in the bowl;

Assemble washer and/or nut onto threads of each fastener beneath thebowl; and,

Tighten the nuts so that torque is sufficient to compress the base ofthe polymeric fastener head and that the tank is level.

While the embodiments of the invention described herein are presentlypreferred, various modifications, improvements and equivalences can bemade without departing from the spirit and scope of the invention. Thescope of the invention is indicated by the appended claims, and allchanges that fall within the meaning and range of equivalents areintended to be embraced therein.

1. A fastener for securing a tank of a toilet to the toilet bowl bothhaving a corresponding bolt receiving opening, said fastener comprising:a threaded bolt including a shank; a head at one end of the shank; aplain end on the opposite end from the head end; a pliable compositionencapsulating the entire bolt head and a portion of the shankimmediately adjacent to the head; the encapsulation having a lower flatface surface below the head and facing the plain end, the encapsulationon the lower flat face surface having an integral o-ring seal configuredextending about the shank to at least partially seal an associated boltreceiving opening, said fastener further including a sealing ribextending about the shank, the sealing rib includes a leading edgefacing the threads and the leading edge is angled toward the head.